match_arg(arg, choices, index = FALSE, several_ok = FALSE, ignore_case = FALSE)
A character vector (of length one unless
several_ok = TRUE).
A character vector of candidate values.
Return the index of the match rather than the match itself? Default no.
argto have length greater than one to match several arguments at once? Default no.
Ignore case while matching. Default no. If this is
TRUE, the returned value is the matched element of
choices(with its original casing).